Abstract Entities

An abstract class may be declared an entity by decorating the class with @Entity. Abstract entities differ from concrete entities only in that they cannot be instantiated.

Abstract entities can be queried just like concrete queries. If an abstract entity is the target of a query, the query operates on all the concrete subclasses of the abstract entity.

@Entity
public abstract class Employee {
    @Id
    protected Integer employeeId;
    ...
}
@Entity
public class FullTimeEmployee extends Employee {
    protected Integer salary;
    ...
}
@Entity
public class PartTimeEmployee extends Employee {
    protected Float hourlyWage;
}